Just cut the seat frames down to 3" all around. you must have at least 3" frames.
It has been done before , search FS 14 in the gallery and if i remember right there is a nice yellow one
built that way. I will be building one similar eventually.

You may want to consider raising the sole to hide the frames closer to the chine. IIRC, if you just maintain 3" of frames and place the sole at the top of the stringers, frames will protrude into the sole almost a foot near the chine.

Just getting started cut parts few weeks ago then we've been in the twenties for few weeks. I got two heaters and a slight warmup yesterday so was able to epoxy all the long parts together finally. Have the strong backs and everything ready to jig up tomorrow.
I've drawn the 3" line around the middle seat frames to fit floor. The line I came up with is 7" above dead bottom middle of boat. Sound about right? I was going to set it up then cut them once flip I was thinking. I'm going to load few pics when home shortly, having some trouble from iPhone.